Air conditioning apparatus



July 20, 1948. N, wElNsTlN- ETAL 2,445,705

AIR CONDITIONING APPARTUS Filed June 1o, 1944 INVENTOR BY J 71( WMATroRNEY Patented .luly 20, 1948 oFFicE 'AIR CONDITIONING APPARATUSNorman Weinstein and Gerald F. Mannion, v

Chicago, lll.

Application June 10, 1944, Serial No. 539,707

Claims. (Cl. 62-6) The object of our invention is to provide anapparatus for conditioning air or gas, particularly when this air or gasmust be conditioned to a temperature at or below the frost point.

Another object of our invention is to provide a sequence of cooling andreheating stages for conditioning air or gas whereby the air or gas maybe economically dehumidied and reheated in a comparatively small space.

Another object of our invention is to provide an apparatus which willcondition air or gas by dehumidifying it and subsequently reheating itso that the air or gas conditioned will have a continuously uniformmoisture content and dry bulb i temperature.

Another object of our invention is to provide a means of control wherebythe conditioned air or gas will be uniform as to moisture content anddry bulb temperature.

Another object of our invention is to provide an apparatus which willallow air or gas conditioned below the frost point to deliver this airor gas on a continual basis without the necessity of using more than onesystem of apparatus for the purpose.

Another object of our invention is to provide an apparatus which willallow air or gas conditioned below the frost point to be delivered on a.continual basis without the necessity of shutting down the apparatus fordefrosting.

Another object of our invention is to provide an apparatus to deliver acontinual flow of air or gas at a constant condition and at the sametime require the use of less refrigeration capacity than normallyrequired.

It is well known that in the use of air or gas where this air or gasmust be dehumidifled to a condition at or below the frost point that aduplexing of equipment is required so that the air or gas can bedelivered constantly without shutting down for removal of ice or frostaccumulations.

' At the same time the total amount of refrigeration The flow of gas orair through our apparatus differs from that previously used or inventedmainly in the following feature: y

Coils 2I and 23 are identical. Coil 2| is used as the nal cooler whengas or air is routed through duct I5. During this cycle coil 23 is be- 2ing defrosted. Coil 23 is used as final cooler when gas or air is routedthrough duct Il. During this cycle coil 2l is being defrosted.

Our invention is not limited to this one feature-but stress is placed onit to clarify the typical example which is given below:

The gure shows diagrammatically the means of accomplishing ourinvention. Referring to the gure, I2 represents an inlet duct or pipewherefrom air or gas is moved by fan I I through either conduits I5or I6, then through casing I2. then through either conduits I5 or I6 tooutlet duct I1. The casing I3 which may be in either a horizontal orvertical position, and is shown In the figure to be raised from theground by supports I0.

As a typical illustration, assume the following conditions:

Gas at F. saturated is to be conditioned to 25 F. saturated when leavingcoil 2| into the duct I6 or leaving coil 23 into duct I5.

This 70 gas enters apparatus through duct I2, into duct I5, throughtransfer valve I4, then into casing I3.

Gas then passes over coil 23, defrosting that coil provided a previouscycle has occurred.

The gas then passes over coil 22, and is reduced to 57.5 F. saturated.Gas then flows over coil 2l and is reduced to 25 F. saturated.

Gas then leaves casing I3, travels through duct I6, through transfervalve I4, and through duct I8 In this problem, the sole purpose ofreducing the gas temperature to 25 F. saturated is the eliminationofvmoisture. Any sensible heat pickup, after that accomplishment, is again. Therefore, gas now travels through heating coil 24 which isinterposed in duct I8. This coil (24) is connected by pipe circuits 30and 3I to cooling coil 22, to form a heat reclamation cycle. A pump 26is intenposed in the pipe circuit (30 and 3|) to circulate the heatexchange medium from c0111.* ing coil 22 to heating coil 24, and backvagain.

Heating coil 24 restores to the gas as sensible heat both the latent andsensible heat which cooling coil 22 abstracted. Thus the gas has beendehumidied to the equivalent of 25 F. saturated. but leaves apparatuswith part of the sensible heat restored which had to be removed fordehumidiflcation.

Conversely, this h'eat reclamation causes the heat exchange medium to bereduced in temperature by the passage of 25 F. gas over heating coil 24.The heat exchange medium, thus reduced in temperature, is returned tocoll 22 at a lower temperature than that at which it left this samecoil, thus causing a direct saving in the amount of refrigerationrequired to reduce the gas temperature to 25 F.

Coils 24 and 22 need only be used when de- 3 sired to raise the outlettemperature of air emit-A ting either from coils 2| or 23.

In this problem the gas now leaves apparatus through duct I1 at a dewpoint temperature of 25 F. but a dry bulb temperature of 60 F,

As in all refrigeration dehumidifying apparatus where it is necessary touse a cooling medium at or below the frost point, ice or frost will formon the coil or other apparatus used for heat transfer purposes. In thisproblem ice has gradually accumulated on coil 2| until its effectivenessas a transfer medium is about to be impaired. The defrosting of coil 2|and the simultaneous transfer of the function of deh'umidiiying andcooling from coil 2| to coil 23, occurs as follows:

The cooling coils 2| and '23 are supplied with a cold heat exchangemedium, preferably brine from the refrigeration unit 2B, through a pipecircuit 42, the ow being controlled by valve 44. The brine circuit isformed by the supply pipe 13 from the refrigeration unit 28 to the valve44 which selectively allows the ow of cooling medium to coil 2| andsh'uts oi the iiow of cooling medium to coil 23, and when actuated bythe motor 10 will shut off the ow of cooling medium to coil 2| and allowthe flow of cooling medium to coil 23.

The cooling medium is returned from coil 2| to conduit 16 throughconduit 14 and the cooling medium is returned from coil 23 to conduit 16through return conduit 15. A pump 11 is interposed in the return conduit16 to pull the cooling medium from the coils back to the refrigeratingunit 28. Interposed in the line 13 is a valve 80, operated by a motor19, actuated by the power line 13, responsive to the thermostat 40 toregulate the amount of flow of the brine. In the sequence of operationdescribed, the cold heat exchange medium is only supplied to coil 2|,the ilow of this medium being shut oi to coil 23 by valve 44. Asaccumulations of ice and frost on coil 2| develop and a reversal of theflow f the gas is made through the actuation of transfer valve I4,causing the air or gas entering casing I3 to pass through inlet I6instead of inlet I5. At the same time valve 44 is -actuated to shift theiiow of the cold brine from coil 2| to coil 23. At the same time valves68 and 69 in pipe circuit 30 and 3| operate to divert the flow of theheat exchange medium in pipe circuit 30 and 3| through pipe 34 and pipe35 so that a reversal of flow of this heat exchange medium takes placein cooling coil 22. The operation of the valves mentioned above may beaccomplished either through an air supply source and air conduits suchas 6I, 62, 83, 34, 65, 66, 13, etc., as shown, or may be accomplished byother well known means such as, for example, an electrical/circuit (notshown). It is advantageous in heat exchange, from a heat exchange mediumto air using a multirow coil, that th'e coolest portion of heat exchangemedium be in contact with the leaving air, .and thus when the directionof the ow of air through the coil (a multirow coil) is changed, thedirection of the ilow of the heat exchange medium through th'e collshould be changed. so that the warmest portion of the heat exchangemedium be in contact with the entering air, and the coolest portion ofthe heating medium be in contact with' the leav ing air.

When the ow of air through the coil 22 is reversed it is also desirableto reverse the ilow of heat exchange iiuid medium through coil 22,without reversing the ilow of heat exchange medium through' coil 24.This is accomplished by the said two way valves 33 and 69, whereby whenthe air enters through conduit I5, the valve 3l would allow a ilow ofheat exchange fluid from conduit 3| through conduit 12, through amultirow coil 22, out through conduit 1I through pump 36 and conduit 30.In this positiorrvalve 63 prevents any fiow through conduit 35, andvalve 68 prevents any flow through conduit 34.

When the air enters through conduit I4, the iiow of heating exchangemedium through coil 22 is reversed by valves 63 and 69, whereby thevalve 58 allows a. flow of heat exchange medium from conduit 3| throughconduit 35 and a portion of conduit 1|. then through the multirow coil22 and out through 12, then through conduit 34 and through the valve 69,pump 36 and conduit 30. In the last operation the position of the valves68 and 69 are both changed from the first operation and shuts oil the owof heat exchange medium from conduit 3| to conduit 12 and allows theiiow of heat exchange medium from conduit 3| through conduit 35v whilethe position of valve 69 shuts off the ilow of heat exchange medium fromthat portion of conduit 1| between the valve 69 and coll 22.

The direction of ilow through the valve 63 is aiways from conduit 3|through the valve either to the conduit 12 or the conduit 35, depending`upon the position of the two-way valve 68, and

the direction of th'e flow through the valve 63 is always toward thepump 36, with the inlet open to allow flow either from conduit 34 orfrom that portion of conduit 12 between the valve 69 and.

' eration of valves 68 and 69. The same electrical circuit 63 operatesthe motor 5|, controlling damper I4, and motor 33. operating valve 69,and motor 32 operating valve.68, so that valves 63 and 69 are actuatedsimultaneously with the operation of damper I4.

From duct or pipe I2, the gas passes through transfer valve I4, throughpipe or duct I6, into casing I3. As this gas Stream passes over coil 2|,the accumulated ice and frost is melted oi and drained out of casing I3.The gas stream then iiows over coil 22 where its temperature is reducedfrom '10 F. saturated to 57.5 F. saturated. This gas then iiows overcoil 23 where its temperature is further reduced to 25 F. saturated. Thestream of air or gas then flows through duct or'pipe I5 from casing I3through transfer valve I4, and then over reheatlng coil 24, where thelatent and sensible heat that is removed by coil 22 is added to the airor gas as sensible heat.

As ice and frost begin to accumulate on coil 23 in the describedsequence of operation, transfer valve is again actuated and the iiow ofair or gas is again reversed through apparatus casing I3. At the sametime valve 44 in pipe circuit 42 is actuated to stop the iiow of brinethrough coil 23 and allow the dow of brine to go through coil 2|. Valve63 and valve 63 in pipe circuit 30 and 3| are also actuated so that theilow of the heat exchange medium through coil 22 is reversed. It isapparent from th'e above description that through the method ofoperation herein used that our invention gives a continual operatingapparatus for the delivery of air or gas at dew points as low as thefrost point or lower without the necessity of shutting down theapparatus for deicing or defrosting or for the necessity of duplexlngthe apparatus.

In order to show further advantages o! the apparatus which we describeherein, we refer to a typical problem of cooling 10,000 C. F. M. of freeair or gas which on entering our apparatus at '10 F. saturated leaves ata final condition of 60 F. dry bulb and 25 F. dew point. 'Iheconditioning of the air or gas as set forth in the above example couldbe obtained by means of a single cooling coil such as coil 2| or 23 witha refrigeration requirement of 90 tons being necessary. However, bymeans' of our method or dehumidifying and reheating we are able toreduce the refrigeration load from 90 tons to 56 tons and at the sametime deliver this gas or air at the same dew point. i

A thermostat 40 responsive to the temperature of th'e air in conduit I8controls the operation of the valve 44 so as tb selectively direct theilow of brine either to coil 23 or coil 2I, and also controls theoperation of transfer valve or damper I4, so as to selectively directthe flow of air to be conditioned either through duct I5 or duct I6, andalso controls operation of the valves 68 and 63, so as to selectivelydirect the flow of heat exchange medium to coil 24 either through pipe3l or pipe 30. Assuming that the coil 23 becomes frosted as to impairth'e operation of the coll, the result in most cases wouldV be to reducethe quantity oi' air being able to pass the coil with a resultant lowerdry bulb temperature. Assuming the thermostat 40 to be set so that areduction in the dry bulb temperature of the air in conduit I8 willcause the thermostat to activate the motors controlling valve I4, valve44 and valves 68 and 69 through the lines 6I, 62, 63, 64, 65 and 66. Themotors are of the commercially reversible type and a time relay 61 (alsocommercially known) is interposed in the line 6I, so as to preclude anyfurther operation of the motors until suflicient time has elapsed toallow the new cycle to take effect and raise the temperature of the airsurrounding thermostat 40, and then when the thermostat 40 againactivates line 6I to cause the motors controlling the operation ofvalves I4, 68, 69 and 44 to reverse their operation. The motorcontrolling the valve I4 is designated as 5I. The motor 32 controls thevalve 68, the motor 33 controls th'e valve 69 and the motor 10 controlsthe valve 44.

The valve or damper I4 is shown by the curved blade 50, which allowsflow of air from conduit I2 to conduit I5 and-from conduit I6 to conduitI6. A 90 revolution of the blade 50, as is shown by the dotted lines,will cause the air from conduit I2 to flow through conduit I6 andthe airfrom conduit I5 to flow through conduit I6.

The valve 44 is a two way valve, which in one position suppliesrefrigerant to coil 23 and sh'uts off the flow to coil 2| and whenrevolved by the motor 'I0 will cut olf the supply to coil 23 and supplyrefrigerant to coil 2I.

The valve 69 is a two way valve in one position to supply heat exchangefluid to coil 22 through pipe 1I and in the second position to -cut offthe supply of heat exchange fluid to .pipe 'II and to supply said fluidto coil 22 through pipe 34.

Valve 68 is a similar twoway valve, which in one position allows a flowof uid from coil 22 through lines 1I, 35 and 3| to coil 24, and inanother position allows a flow of fluid from coil 22 through lines 12and 3I to coil 24.

The damper I4 is circular operatively connected with conduits I2, I5, I6and I8, so that the position of the blade or damper It will selectivelydlrect the air from conduit I2 to either conduit Il or I6.

If it is desired to control the operation oi' the 5 said :rotors andvalves responsive to an interval of time. then a device designed tooperate a motor upon the lapse of a predetermined interval of time maybe substituted for thermostat 40, or an instrument responsive to theaccumulation of frost on cooling coils 2| or 23 may be substituted forthe thermostat 4II. We claim: )1. An air conditioning apparatuscomprising a casing with vair inlet and outlet, means to move airtherethrough, two cooling coils interposed in said casing in the path ofsaid air, and meansto reverse the flow of air through said casing, andmeans to alternately supply refrigerant to one and then the other ofsaid cooling coils, a third .20 cooling coil interposed in said casingbetween said first mentioned cooling -coils and operatively connected byconduits containing heat exchange medium with a reheating coilpositioned in the path -of the air emitting from said outlet.

2. An air conditioning apparatus comprising a casing with air inlet andoutlet, means to move air therethrough, two cooling coils interposed insaid casing in the path of said air, and means to reverse the flow ofair through sai-d casing, and means to alternately supply refrigerant toone and then the other of said cooling coils, a third cooling coilinterposed in said casing. between said first mentioned cooling coilsand operatively connected by conduits containing heat exchange medium3'5 with' a reheating coil positioned in the path of the air emittingfrom said outletmeans to change the direction of ilow of heat exchangemedium through said third cooling coil responsive to the temperature ofthe air emitting from said outlet.

3. In an air conditioning apparatus comprising a casing with air inletand outlet, means to move air through said casing and through a firstcoil and then through a second coil, said coils being spaced in saidcasing, means to reverse the direction of the flow of air through saidcasing and the first and second coil, and means to selectively .supplyrefrigerant to either one of said coils and on reversal of flow of airto cut olf the refrigerant to the coil lsupplied and supply refrigerantto the other of said coils.

4. In an air conditioning apparatus comprising a casing with air inletand outlet, means to move air through said casing and through a firstcoil and then through a second coil, said coils being spaced in saidcasing, means to reverse the direction of the flow of air through saidcasing land the first and second coil, means to supply refrigerant towhichever of said coils is last in the path 'of said air and to cut offthe supply of refrigerant to the coil first in the path of said air.

5. In an air conditioning apparatus comprising a casing with an Vairinlet and outlet vand two spaced coils therein and means to move airthrough' said casing and first through one coil and then through theother, means to reverse the flow of air and means to supply refrigerantto one of said coils and on reversal of flow of air to cut off thesupply of refrigerant to the last named coil and supply refrigerant tothe other coil.

6. In an air conditioning apparatus comprising a casing with an airinlet and outlet two spaced cooling coils in said casing, means to moveair through said casing and successively through said coils and means toreverse the il'ow of said air, means to alternately supply refrigerantto first one and th'en the other of said cooling coils. both of saidlast two means being responsive to conditions indicating that one ofsaid coils has become frosted.

7. In an air conditioning apparatus comprising a casing with an airinlet and outlet, and two spaced cooling means therein, means to moveair through said casing and first through one cooling means and thenthrough the other. means to reverse the flow of air, and means to supplycooling medium to one of said cooling means and on reversal of the flowof air to cut olf the supply of cooling medium to th'e last mentionedcooling means and supply cooling medium to the other said cooling means.

8. In an air conditioning apparatus comprising a casingwith an air inletand outlet. two spaced coils therein, and means to move air through saidcasing and first through one of said coils and then through the other ofsaid coils, means to selectively reverse the flow of air and means tosupply refrigerant to one of said coils and on reversal of flow of airto out off' the supply of refrigerant to the last named coil and supplyrefrigerant to the other coil.

9. In an air conditioning apparatus comprising a casing with air inletand outlet, means to move air through said casing and through a firstcoil and then through a second coil, said coils being spaced in saidcasing, means to reverse the direction of the flow of air through saidcasing and the first and second coil, means to supply refrigerant towhichever of said coils is last in the path of said air and to cut ofi'the supply of refrigerant to the coil first in the path of said air,both of said last two means being responsive to conditions indicatingthat one of said coils has become frosted.

10. In an air conditioning apparatus comprising a casing with air inletand outlet, means to move air through said casing and through a firstcoil and then through a second coil, said coils being spaced in saidcasing, means to reverse the direction of the flow of air through saidcasing and the first and second coil, and means to selectively supplyrefrigerant to either one of said coils and on revers-al of ow of air tocut olf the refrigerant to the coil supplied and supply refrigerant tothe other of said coils, both of said last two means being responsive toconditions indicating that one of said coils has become frosted. l

11. In an air conditioning apparatus comprising a casing with an airinlet and outlet and two spaced coils therein and means to move airthrough said casing and first through one coil and then through theother, means to reverse the flow of air and means to supply refrigerantto one of said coils and on reversal of flow of air to cut off thesupply of refrigerant to the last named coil and supply refrigerant tothe other coil, and a reheating coil positioned in the outlet of saidcasing to reheat the outgoing air after it has left the last of saidcooling coils.

between said first mentioned cooling coils and operatively connected byconduits containing heat exchange medium with a reheating coilpositioned in the path of air,emitting from said outlet.

.13. In an air conditioning apparatus comprising a casing with an airinlet and outlet and two spaced coils therein and means to move -airthrough said casing and first through one coil and then through theother, means to reverse the fiow of air and means to supply refrigerantto one of said coils and on reversal of flow of air to cut off thesupply of refrigerant to the last named -coil and supply refrigerant to'the other coil, a

third cooling coil interposed in said casing between said rst mentionedcooling coils and operatively connected by conduits containing heatexchange medium with a reheating coil positioned in the ,path of the airemitting from said outlet and means to change the direction of flow ofheat y to alternately supply refrigerant to one and then the other ofsaid heat exchangers, a third heat exchanger interposed in said casingbetween said first mentioned heat exchangers, a reheat exchanger at theoutlet of said casing in the path of air flowing through said outlet,conduits connecting said reheat exchanger and said third heat exchangerfor circulation of heat exchange fluid therethrough.

15. An air conditioning apparatus comprising an elongated duct, two heatexchangers in said duct, an air valve having four openings therein, afirst conduit connecting the first of said openings to one end of saidduct, a second conduit connecting the second of said openings to thevother end of said duct, the third of said openings serving as an airsupply opening, a third conduit connected to the fourth of saidopenings, said valve having movable means which in one position connectsthe rst and third openings and the second and fourth openings forpassage of air and in another position connects the first and fourthopenings and the second and third openings for passage of air, means tomove air in,- wardly through said third opening and through said ductand`conduits, a third heat exchanger in said duct interposed betweensaid two heat exchangers, and a fourth heat exchanger in said thirdconduit, means for circulating a heat exchange fluid between said thirdand fourth heat exchanger, and means for selectively supplying heatexchange medium to one of said first mentioned two heat exchangers.

NORMAN WEINSTEIN.

GERALD F. MANNION.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date y2,008,407 Stoever July 16, 19352,200,118 Miller May 7, 1940 2,215,327 Karsten Sept. 17, 1940

